fix(frontend): unbreak single post layout cascade

Disable the global 2-col .content-layout grid on single pages (it was
tiling breadcrumb/article/author/related/comments left-right), add the
missing Zibll utility bridge used by the author/meta bar, and replace
nonstandard <name>/<item>/<badge> tags in the single surface.

assets/css/frontend/single-post.css

@@ -1,3 +1,4 @@
+@import url("zibll-utilities.css");
 @import url("single-post/shell.css");
 @import url("single-post/content.css");
 @import url("single-post/code-blocks.css");